1. Field of the Invention
Gasoline compositions are highly refined products. Despite this, they contain minor amounts of impurities which can promote corrosion during the period that the fuel is transported in bulk or held in storage. Corrosion can also occur in the fuel tank, fuel lines and carburetor of a motor vehicle. As a result, a commercial motor fuel composition must contain a corrosion inhibitor to inhibit or prevent corrosion.
Internal combustion engine design is undergoing changes to meet new standards for engine exhaust gas emissions. One design change involves the feeding of blow-by gases from the crankcase zone of the engine into the intake air supply to the carburetor rather than venting these gases to the atmosphere as in the past. Another change involves recycling part of the exhaust gases to the combustion zone of the engine in order to minimize objectionable emissions. Both the blow-by gases from the crankcase zone and the recycled exhaust gases contains significant amounts of deposit-forming substances which promote the formation of deposits in and around the throttle plate area of the carburetor. These deposits restrict the flow of air through the carburetor at low speeds so that an overrich fuel mixture results. This condition produces rough engine idling or stalling causing an increase in the amount of polluting exhaust gas emissions, which the engine design changes were intended to overcome, and decreasing fuel efficiency.
An acceptable motor fuel requires additives addressed to correcting or inhibiting the noted disabling characteristics of motor fuels. Thus, the discovery of a novel and cost effective motor fuel additive capable of general application which combines good detergency properties with effective corrosion inhibition will provide a material advance in the state of the art.
2. Description of the Prior Art
Copending application Ser. No. 190,687, filed Sept. 25, 1980, now abandoned discloses a motor oil dispersant and a process for making the same. The motor oil dispersant disclosed is prepared by condensing an alkenylsuccinic anhydride having an alkenyl group of at least 64 carbon atoms in the presence of a basic catalyst to form an intermediate spirodilactone and then reacting the intermediate spirodilactone with a polyamine or polyamine alcohol to form the dispersant reaction product.
Walter Reppe et al., Ann. 596,158 (1955), reported the conversion of succinic anhydride to the spirodilactone derived from 4-ketopimelic acid by heating at 190.degree.-200.degree. C. in the presence of sodium benzoate (weak base) catalyst as follows: ##STR1##
U.S. Pat. No. 4,104,477 is of interest for disclosing spirodilactones prepared by heating alkenyl or alkyl bis (succinic anhydrides) to the temperature at which one mole of CO.sub.2 is lost.